Forensic Science and Early Detection

Books reviewed by Paul Magrath

Forensics: The Anatomy of Crime by Val McDermid

(Profile Books, £18.99)

The Suspicions of Mr Whicher by Kate Summerscale

(Bloomsbury, £8.99)

Val McDermid is a crime writer with a reputation for gritty psychological thrillers and her approach in Forensics: The Anatomy of Crime is that of an outsider with a professional fascination for the tricks of another’s trade. Or rather trades, because, as she explains, there are many branches of science involved. And she has spent time with many of the scientists who ply these trades, picking their brains and nicking some of their best anecdotes.

We tend to think of forensics as something belonging to the modern world – the world of fingerprints and DNA and white-coated lab technicians. But McDermid takes it at least as far back as thirteenth century China, where a Chinese official named Song Ci wrote a handbook for coroners entitled The Washing Away of Wrongs. This recounted the earliest recorded example of forensic entomology – the use of insect biology in the solution of a crime.

The victim had been stabbed to death by the roadside. Having concluded from the shape of the wounds that the murder weapon was a sickle, the coroner ordered all the 70 adults in the neighbourhood to stand in a line, their sickles at their feet. There were no visible traces of blood on any of the sickles. But within seconds a fly landed enthusiastically on one man’s blade, attracted by minute traces of blood. The owner of the blade turned out to be a money lender whose debt the victim had been unable to satisfy. Confronted by the fly’s testimony, he made a full confession.

Until the late nineteenth century, when evidence-based legal proceedings became the norm, McDermid says that the preservation of evidence at crime scenes remained rudimentary. Nowadays, cross-contamination of evidence is often a big issue. And the more scientists have been able to learn and testify about the evidence, the more critical its collection and analysis have become.

McDermid quotes Peter Arnold, a crime scene investigator (CSI) for the Yorkshire and Humberside Scientific Support Services, who describes his role:

“The scene is the silent witness. The victim can’t tell us what happened, the suspect probably isn’t going to tell us what happened, so we need to give a hypothesis that explains what has taken place.”

A key figure in the understanding of crime scenes was the Frenchman Edmond Locard, who opened the world’s first crime investigation laboratory in 1910. He is famous for the phrase, known as the Locard Exchange Principle: “Every contact leaves a trace”. It might be fingerprints, footprints, fibres, hair, skin or something as obvious as a discarded weapon.

The counterpart is another familiar phrase: “Absence of evidence is not evidence of absence.” Between these two bookends lies the spectrum of what forensic science can, and cannot, discover.

McDermid takes us through the different sciences involved, in a series of chapters on fire scene investigation, entomology, pathology, toxicology, fingerprinting, blood spatter and DNA, facial reconstructions, digital forensics, forensic psychology and, finally, what happens when the expert witness reaches the courtroom and has to explain it all in lay person’s terms to a jury and then defend it against the challenges of cross-examination.

Written with pace and clarity, Forensics is the perfect introduction for the curious lay person and the bare minimum on the subject that any student of criminal law ought to have read.

***

A good example of the way forensic science was used in its comparative infancy, in the Victorian period, is Kate Summerscale’s book, The Suspicions of Mr Whicher, or the Murder at Road Hill House. This was hailed on its publication a few years ago as a masterpiece in the genres both of social history and of crime and detection, and you can see why. Summerscale takes the case of a gruesome murder of a small boy in a prosperous middle class home and examines it in the context of the early development of the police force and professional detectives, and the personal history of one particularly famous detective, Jack Whicher, whose reputation came under fire in consequence of his unorthodox (but ultimately correct) analysis.

The story is a sad one, but also fascinating for the light it throws on the way society was changing in the early 1860s, as Victorian values took hold in a nation coming to terms with its growing prosperity and power in the world. It was a time when an Englishman’s home was very much his castle, albeit a castle peopled with servants, and where the father of the family could not be questioned either by wife and children or even, to a large extent, by figures in authority such as policemen, doctors and lawyers, let alone prying journalists from the national press. All these certainties were challenged in the course of the investigation.

The science was, however, rudimentary and still subject to the limits of Victorian notions of delicacy, as witnessed by the treatment of undergarments. A key piece of evidence, according to Mr Whicher, was a mysteriously missing nightdress worn by one of the other inhabitants of the house on the night of the murder. Had it been accidentally “lost” by the laundress, or deliberately removed to conceal the fact that it must have had blood stains? While examining the house, one of the policemen came across another undergarment, described as a “shift” or “shimmy”. It was badly stained, but probably only with menstrual blood (described as “natural causes”), and also (given its nature and condition) evidently belonging to one of the servants. This was not only discounted by the police as irrelevant to the investigation but was not even mentioned to the London detective, Mr Whicher, when he was called in to investigate the case. As it happened, the shift wasn’t relevant, but its embarrassed suppression is typical of the assumptions of the day.

The murder captured the imagination of the Victorian public, as well as a number of more famous observers, including Charles Dickens (who identified the wrong suspect, as it happened); and in Kate Summerscale’s book it has captured our own as well. It is not hard to see why. Though our social values are quite different, the quest for truth is eternal. And as Val McDermid has also demonstrated, there is nothing quite so satisfying as applying science and logic to an apparently intractable problem, and reaching a hypothesis which turns out to be the correct solution.

***

If you’re interested in forensic science and want to know more about it, you could also take a look at one of the FutureLearn free online courses which deal with the subject. There’s an Introduction to Forensic Science, offered by the University of Strathclyde. This is already in progress (I tried it this time last year) but it will probably be run again next year. There’s Forensic Psychology: Witness Investigation, offered by the Open University, from 16 March. And there’s Forensic Science and Criminal Justice, offered by the University of Leicester, from 13 April.